Belt cleaners for belt sanders



Oct. 27, 1970 E. c. DUDEK 3,535,829

BELT CLEANERS FOR BELT SANDERS Filed May 21, 1968 2 Sheets-Sheet lINVENTUR.

I Edmund C. Dude/r V ATTORNEY Oct, 27, 1970 E. c. DUDEK 3,535,829

BELT CLEANERS FOR BELT SANDERS Filed Maya, 196s 2 Sheets-Sheet 2INVENTOR.

' Edmund C. Dude/r W/TNESS Y A TTORNE Y United States Patent O 3,535,829BELT CLEANERS FOR BELT SANDERS Edmund C. Dudek, Oakbrook, Ill.,assignorI to The Singer gompany, New York, N.Y., a corporation of Newersey Filed May 21, 1968, Ser. No. 730,763

' Int. Cl. B24b 23/00, 55/00 U.S. Cl. 51-170 8 Claims ABSTRACT OF THEDISCLOSURE .'Ihis disclosure relates to a belt cleaner for a belt sanderin which a portion of the motor cooling air is delivered at highvelocity through nozzles or holes upon the upper sides of the belt as itmoves past the motor housing substantially between the drive and idlerpulleys to blow olf the packed dust and debris that has collected on thesanding belt.

BACKGROUND OF THE INVENTION In the prior art the sanding belt of a beltsander was cleaned manually, which proved to be both time consuming andgenerally ineicient. Furthermore, the longer a particular belt was usedthe more frequent the sanding operation had to be interrupted to cleanthe belt due to clogging and collection of the dust and debris thereon.

A partial solution has been the use of a dust pickup system i-n which abuilt-in or otherwise attached vacuum cleaner is used in combinationwith the belt sander to remove dust and debris from the work surface inthe immediate area of the belt sander, usually at the rear of the basethereof. While this may be helpful, in that it tends to limit thebuildup of dust, it is not the ultimate solution since it failed toprevent the dust from packing on the sanding belt.

SUMMARY OF THE INVENTION In accordance with the present invention thenovel belt cleaner is provided for a belt sander having a motor mountedinto the frame thereof, Which frame rotatably supports a pair of spaceddrums one of which is driven by the motor and upon which a sanding beltis operatively connected. The motor is cooled by a fan drawing airthrough a motor housing of the frame disposed adjacent the sanding beltand separated therefrom by a partition Wall. A plurality of nozzleapertures or holes are formed in the partition Wall to direct a portionof the cooling `air at high velocity into contact with and against theabrasive surface of the sanding belt so as to loosen and substantiallyremove the collected dust and debris thereon. In some types of beltSanders the belt cleaner fan may be separately housed or the nozzleslocated remotely from the motor or fan housing in a suitable wall orconduit.

It is therefore an object of the present invention to provide animproved belt cleaner for belt sanders which overcomes the prior artdisadvantages; which is simple, economical and reliable; which combinespneumatic cleaning of the sanding belts with vacuum pickup of the dust;which has pneumatic cleaning of the sanding 3,535,829 Patented Oct. 27,1970 ice belt by high velocity air; which has pneumatic cleaning of thesanding belt substantially along the full width thereof; which has anadjustable outlet nozzle to control the velocity and volume of pneumaticair directed to clean the sanding belt; which has an adjustabledischarge from the motor housing to selectively increase the portion ofair delivered through the pneumatic nozzles to clean the sanding belt;which controls the passage of air through the motor housing to adjustthe quantity and volume of the air passing through the nozzles to cleanthe sanding belt; and, which permits cleaning of the sanding beltwithout adversely affecting the motor cooling.

Other objects and advantages will be apparent from the followingdescription of several embodiments of the invention and the novelfeatures will be particularly pointed out hereinafter in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS This invention is illustrated in theaccompanying drawings in which:

FIG. 1 is a sectional View taken through the motor housing and base ofthe frame of a belt sander embodying one form of the present invention.

FIG. 2 is a perspective view, partially exploded, of the belt sanderembodying another form of the present invention.

FIG. 3 is a sectional top plan view taken above the partition wall ofthe motor housing looking downwardly toward the base of the belt sanderof FIG. 2.

FIG. 4 is a side elevational view, partly in section, of the belt sanderhaving an integral dust pickup system, and embodying still another formof the present invention.

DESCRIPTION OF THE INVENTION In the present invention, one form is shownin FIG. 1, another form is shown in FIGS. 2 and 3, and still anotherform is shown in FIG. 4; but in all cases, the present invention isembodied in an otherwise conventional belt sander 10', which machineremains basically unchanged, except for the addition of an integral dustpickup system 11 depicted in FIG. 4, and of course, the differentcomponent parts of the various forms of the present invention.

Accordingly, the portable belt sander 10, illustrated in FIGS. l, 2 and4 has a main frame or housing 12 v including a side wall 14, and endwall 16, and a substantially horizontal upper wall 18. Rising from theupper wall 18 and integral with the frame 12 is a cylindrical motorhousing 20 within which is mounted an electric driving motor 22 having ashaft 24 journaled longitudinally within the housing 20, and transverseto the frame 12.

The frame 12 supports a pair of revolvable drums or pulleys 26 and 28located adjacent the longitudinal ends thereof, and an endless ilexiblesanding belt 30` is trained over the drums. The forward drum 26 is theidler drum, while the rearward drum 28 is the driving drum and isoperatively connected and driven by the electric motor 22.

The motor shaft 24 carries a toothed pulley 32, illustrated in FIGS. 1and 4, which drives a timing belt 34 the other end of which drives atoothed pulley suitably 36 mounted to the frame 12 by a stub shaft 38.The stub shaft 38 carries a pinion 39 which meshes with and drives agear 40 fixed for rotation with the driving drum 28. It will be seenfrom FIG. 4 that clockwise rotation of the shaft 24 results incounterclockwise rotation of the drum 28 thereby moving the lower ply ofthe belt 30 rearwardly along the base of the housing 12. A sole plate 41provides a backing support for the sanding belt 30 as the abrasivesurface thereof is pressed against the surface of the work piece.

The belt sander is conveniently carried or manipulated by a handle 42cast integrally with the motor housing and having a forward grip portion44 and an aft grip portion 46.

The electric motor 22 has an armature 48 and a commutator carried on theshaft 24 with a field 52 disposed in superposition to the armature 50,with dielectrically mounted brush assemblies (not shown) engaging thecommutator 50. Stacked steel laminations make up the core for thearmature 48 and the field 52, about which is disposed an armaturewinding 54 and a eld winding 58, respectively. An electricallyconducting cable is connected to a conventional source of electricalpower and extends into the rear of the handle 42 to be suitablyconnected in circuit with a slide switch 62 and the motor 22, whichmotor is operated upon actuation of the switch 62 in the usual manner.

The motor housing 20 is formed with a cylindrical body portion 64extending transversely of the frame 12 and a common portion with thehorizontal upper wall 18. A centrally apertured closed end 66 journalsthe motor shaft 24 at the drive pulley 32 end and has a plurality ofelongated slots 68 therein serving as inlets for cooling air. A fan 70is seated on the shaft adjacent the opposite open end 72 which is closedby an end cover 74 which journals the other end of shaft 24 and isthreadedly secured by screws 76 to the body portion 64. The end cover 74has an inwardly extending annular flange 78 having an elongated slot 80extending along the bottom thereof adjacent to which is carried a baffleplate 82 which among other things properly orientates the seating of thecover 74 within the cylindrical body portion 64. A plurality ofelongated horizontal slots 84 are formed in the vertical wall of thecover 74 to serve as an outlet for the cooling air which had been drawninto the motor housing 20 through the inlet slots 68.

A belt guard 86 is suitably connected to the frame 12 of the sander 10shown in FIG. l to cover the timing belt 34 and prevent accidentalcontact therewith. However, as shown in FIG. 4, when the dust pickupsystem 11 is used in combination with the belt sander 10 a cover element88 replaces the belt guard 86 which element includes a belt guardportion 90 and suction conduit 92 separated from the guard portion by atransverse partition 94. The cover element 88 is secured to the frame 12by means of a threaded screw 96. The belt guard portion 90 houses thebelt 3.4 and communicates with the atmosphere through a series ofVentilating apertures 98.

A dust chamber is formed on the underside of the upper wall 18 and isbounded by the side walls 14 and end wall 16 to dene the opening inwhich the sanding belt 30 is mounted upon the pulleys 26 and 28. The endwall 16, as shown in FIG. 4, includes an integrally formed passage 102the lower end of which opens to communicate with the dust chamber 100,and the upper end of which connects into the conduit 92. The upper endof conduit 92 is connected through a line 104 the other end of whichconnects into the inlet of a molded plastic scroll housing 106, theoutlet of which is shown at 108 to carry a dust collection bag 110. Ablower impeller 112 is centrally disposed in the housing 106 and isconnected to the outboard end of the toothed pulley 32 to be driventhereby. The housing 106 may be suitably secured to the cover element 88by cementing or the like. Upon operation of the belt sander 10 dust isexhausted from the chamber 100 into the passage 102 which leads throughconduit 92 and line 104 to the blower 112 for discharge through outlet108 into the bag 110 so as to complete the cycle operation of the dustpickup system 11.

In the embodiment of the invention, illustrated in FIG. 1, a pluralityof holes are formed at the fan end of the cylindrical body portion 64 atthe portion thereof common with the horizontal upper wall 18, whichcommon portion is generally designated as 119. The holes 120 aredisposed under the slot 80 of the end cover 74 and between said endcover and bale plate 82. The holes 120 are formed along the full lengthof the common portion 119 at varying distances from the outer end ofsaid portion. The holes 120 may be formed by 'drilling or diecasting ina suitable nozzle shape at varying angles of inclination to direct astream of high velocity all along substantially the entire width of thesanding belt 30, as represented by the arrows 112 exiting from the holes120 in FIG. l.

The holes 120 in the FIG. 1 embodiment are substantially the same as theholes 120 shown in the FIGS. 2 and 3 embodiment of the presentinvention, so that they may all be viewed together.

A portion of the air drawn by the fan 70 through the inlet slots 68 tocool the motor 22 will be delivered for discharge through the holes 120.The supply of a predetermined volume of belt cleaning air is ensured byproviding a baille plate 82 spaced inwardly from the upper opening ofthe inwardmost hole 120 serves to form a chamber 124 from which the airexits through holes 120` to impinge directly upon or flow transverselyalong the width of the sanding belt 30. The cleaning air acts to blowaway the dust and debris which would otherwise collect thereupon, whilethe baille 82 sets the transverse limits of the upper opening of holes120 within the common portion 119. The holes 120 extend underneath thebale plate 82 so that the discharge side thereof lies past the midwaypoint of the sanding belt 30 at an inclination which causes the directstream of air passing therethrough to impinge the sanding belt 30 at apoint three quarters the way in from the outer end thereof. In this wayit will be seen that though the holes 120 have their upper openingsconned to the chamber 124, the discharge side of said holes are not solimited, and may in fact deliver air along the greater portion of theentire width of the sanding belt 30.

The FIGS. 2 and 3 embodiment of the present invention includes anadjustable closure member having a plurality of slots 132 formed toalign with the slots 84 of the end cover in an adjustable manner. Theend cover carries a stud 134 that passes through an elongated verticalcentral slots 136 to threadedly engage a nut 138 having an enlargeddiamond knurled head 140 which enables easy operator turning thereof. Inthe normal position the slots 132 in the member 130 will be in perfectalignment with the slots 84 in the end cover 74. The effect of this willbe to duplicate the belt cleaning results obtained in the embodimentshown and described in FIG. l in that a predetermined portion of thecooling air will be diverted from the discharge slots 84 into chamber124 for discharge through the holes 120 along substantially the fullwidth of the sanding belt 30. If it is desired to change the proportionsof air exiting the slots 84 and holes 120 the embodiment shown anddescribed in FIGS. 2 and 3 illustrates one way in which this may bedone. The operator will grasp the head 140 to turn and loosen the nut138 to allow the member 130 to be shifted along the connes of the slot136 to an adjusted position whereby the slots 132 overlap the slots 84and effect at least a partial closing thereof. The nut 138 is thentightened to clamp the member 130 in the adjusted position. This has thedual result of reducing the total throughput of cooling air andincreasing the total quantity of cleaning air passing through holes 120.Of course, the slots 184 should not be closed to the point which wouldcause motor over heating, but since the extent of the closure of theslots 84 is somewhat dependent upon the load of the motor 22 it remainsfor the operator to determine the most beneiicial setting of the member30.

In the embodiment of the invention shown in FIG. 4 provisions have beenmade to flatten the stepped common wall, designated generally as 119a,and once again form a plurality of nozzle shaped holes 120a thereinthrough which high velocity cleaning air will be discharged against theupper surface of the sanding belt as characterized by the arrows 122a.In this embodiment the throughput flow of the cooling air is neverlessened so as to completely remove operator judgment or the danger ofoverheating the motor 22, instead a slide Valve member 156 extendsthrough a slot (not shown) located in line with the fan 70 and on therearward side of the cylindrical body portion 64, just above the levelof the upper wall 18. This places a plate portion 152 of the member 150in superposition to the openings 120a. The plate portion 152 has aplurality of apertures 153 therein adapted to align corresponding to theopenings 120a, and thus permit a maximum flow of cleaning air throughthe holes 12.001. Pins 154 are fastened to the walls and extend intoelongated slots 155 formed at opposite ends of the slide plate 152 tolimit the movement thereof, while permitting the operator to move ahandle 156 and change the relative position of the apertures 153 withrespect to the holes 120g. This will reduce the size of the openings ofhole 120a and modify the nozzle effect thereof so as to change thecharacteristics of the cleaning air. The changed characteristics of thecleaning air may be highly desirable for certain sanding operationswhich do not require the full velocity force of the cleaning air streamupon the upper surface of the sanding belt 30, and one apparent resultwill be an increased life for said belt.

In the FIG. 4 embodiment of the present invention the dust and debrisblown from the sanding belt 30 passes from the dust chamber 100 to becollected in the dust pickup system 11 and ultimately be collected inthe bag 110. In other words combining the present invention with thedust pickup system 11 prevents the formation of clouds of dust anddebris which otherwise would interfere with the operator visibility andpermits longer periods of uninterrupted operation of the belt sander 10.

Regardless of which embodiment of the invention is used the principlesof operation remain unchanged since as the sanding belt is packed withdust its ability to sand is continuously deminishedyln summary, aportion of the motor cooling air is fed through nozzle-like holes oropenings 120 in the frame 12 wall in superposition to the upper surfaceof the sanding belt 30 which air impinges or passes at high velocitythereover to remove all or a large portion of the packed dust and debrison said belt to clean the same.

It will be understood that various changes in the details, materials,arrangements of parts and operating conditions which have been hereindescribed and illustrated in order to explain the nature of theinvention may be made by those skilled in the art within the principlesand scope of the invention as expressed in the claims.

Having thus set forth the nature of the invention, what I claim hereinis:

1. A belt cleaner device for a portable power operated sander having aframe in which a pair of laterally extending drums are rotatably mountedon the frame to support an endless sanding belt thereon and be driven bya motor carried by the frame, said belt cleaner device comprising:

(a) a housing having a fan portion,

(b) a fan means rotatably disposed in the fan portion of the housing tobe operatively driven by the motor, and

(c) nozzle means disposed adjacent to the sanding belt, and incommunication with the fan portion of the housing to deliver a stream ofair upon the sanding belt substantially to remove packed dust and debristhereon.

2 The combination claimed in claim 1 wherein:

(a) the housing has the motor mounted therein,

(b) the housing is connected to the frame above the sanding belt, (c)the fan portion of the housing includes a wall means disposed adjacentto the sanding belt, and (d) the nozzle means are formed in said wallmeans to deliver streams of air across the width of the sanding belt toclean the same.

3. The combination claimed in claim 2 wherein:

(a) the fan means draws air through the housing to cool the motor, and

(b) a baille means is disposed in the housing to define chamber meansfor the nozzle means and to aid in delivering a portion of the coolingair for discharge through said nozzle means.

4. The combination claimed in claim 3 wherein:

(a) the nozzle means are disposed in spaced relation to each other atvarying angles of inclination to direct streams of air substantiallyacross the width of the sanding belt.

5. The combination claimed in claim 3 wherein:

(a) the housing has inlet and discharge apertures through which thecooling air passes, and

(b) a closing member adjustably mounted to the housing adapted toselectively partially close the discharge aperture whereby a smallerthan normal portion of the cooling air is discharged from said dischargeaperture, and a larger than normal portion of the cooling air isdirected through the nozzle means.

6. The combination claimed in claim 3 wherein:

(a) a plate means is shiftably mounted in the fan portion of thehousing, and

(b) the plate means has a plurality of apertures therein normallydisposed in alignment to the nozzle means and adapted to be operatorshifted to reduce the size of the opening for the nozzle means.

7. The combination claimed in claim 6 wherein:

(a) a handle is formed on the plate means to extend outwardly of thehousing, and

(b) the plate means andthe handle defining a slide valve slideablymounted in said housing.

8. The combination claimed in claim 3 wherein:

(a) a dust pickup system operatively connected to said sander, and

(b) said belt cleaner device to blow the dust and debris from thesanding belt whereby said dust and debris will be collected by the dustpickup system.

References Cited UNITED STATES PATENTS JAMES L. JONES, JR., PrimaryExaminer U.S. C1. X.R.

